1. Field of the Invention
The present invention relates to a video projector and, more particularly, to a video projector with a monitor screen that is capable of causing an image displayed on a transmission-type display means, such as a transmission-type liquid-crystal panel, to be projected on an enlarged scale to a position ahead of a projection lens, and also capable of causing such an image to be projected on a monitor screen provided on the casing of the apparatus.
2. Description of the Related Art
In recent years, the use of camera-integrated video tape recorders (VTRs) has rapidly spread as their size and price have been reduced. It is desirable to have, for use with such VTRs, a monitor capable of inputting a video signal at any time and any place so as to obtain an image. Examples of such monitors are a small liquid-crystal monitor and a small liquid-crystal projector.
A small liquid-crystal monitor (liquid-crystal TV) in which light is projected by a fluorescent lamp or the like from behind a liquid crystal panel is constructed to enable the viewing of an image even in a relatively bright place. However, since a liquid crystal panel of three to four inches is used, the monitor is expensive. Another disadvantage is that the screen is too small to enable viewing by a large number of people.
In a small liquid-crystal projector, a light source illuminates an image displayed on a small liquid-crystal panel, and image light transmitted through the panel is projected on an enlarged scale through a projection lens. With such a projector, it is possible to view a relatively large image. However, the projector can be used only in relatively dark places.
In view of this disadvantage, Japanese Patent Laid-Open No. 2-304591 proposes a small liquid-crystal projector including a screen box which can be freely mounted on and dismounted from the casing of the projector, so that it is possible to view an image even in relatively bright places.
However, it is troublesome to mount or dismount the screen box on or from the casing of the small liquid-crystal projector. Further, in order that the screen box in its mounted position show images projected at relatively great enlargement magnifications, it is necessary to increase the distance from the projection lens to the screen, and hence, the size of the screen box.